After the suicide of 17-year-old Carlos Rojo, life started to unravel as his parents' 23-year marriage collapsed under the strain of grief and loss.The Plainville, Ill., couple had filed for divorce, and was, by all appearances, amicable.

But this week, as they were taking a walk with the dog in a neighborhood on Chicago's north side, Alexander Rojo shot his wife Nancy eight times, sat down on the curb and then shot himself. The 51-year-old Cook County Jail corrections officer had only the day before completed his 14th Chicago Marathon, which he called a "stress reliever."

"Some who knew him through work knew he'd been experiencing some difficulties in his personal life, but nothing that caused any concern," said Steve Patterson, spokesman for the sheriff's office. "They never saw any signs of distress or thought he could do anything like this. They're all stunned."

The Chicago Tribune reported that Nancy Rojo had been in a deep depression and could not work, and the couple had been plagued with financial problems, including two bankruptcies in 10 years. But family and friends said the overwhelming pain of their son's suicide in 2005 -- he fatally shot himself -- had been the main trigger.

Grief experts say that the death of a child, especially a violent death like a suicide, can take a heavy toll on a marriage. "There is a lot of guilt and shame after a violent death," said Ursula Weide, a clinical psychologist and grief specialist from Alexandria, VA. After the traumatic death of a loved one, people may feel anger, irritability and hyperactivation, according to Weide. It's a feeling of "running on adrenaline" or "I am going to explode." "It can easily be turned against the other individual," she said. "The grief and pain weigh on you, and it can activate fight or flight. It can push you beyond the strength you normally have."

"Parents can survive the traumatic death differently." said Weide. "They are not grieving in the same way...But who knows what else was going on between the husband and wife at the time. All this is speculation and we may never find out."

Roja was honorably discharged from the U.S. Marine Corps in 1983 and worked in security jobs until 1998, when he came to work as a correctional officer. "He had no disciplinary history or troubles at work," said Patterson. "He was a mentor to some of the younger officers and used his own physical fitness as a motivator to some of them to work harder."

But in September, Nancy Rojo, 53, accused her husband of threatening to kill her at gunpoint in their home, according to local reports and court records. She said Alexander Rojo slammed her against a basement door, cocked his gun to her cheek and cried, "I'm going to kill you." "He came at me like a raging bull" and "swung me in the air like a rag doll," she said, according to court records. Nancy Rojo said she spent three hours on the floor in fetal position before her husband called police and claimed she tried to kill herself. Alexander Rojo filed an order of protection against his wife, and she countered two days later with one against him.

Nancy Rojo filed for divorce on Sept. 21 and six days later the pair had their protection orders dismissed and agreed to no contact. But on Oct. 16, as the couple took a walk in the Edgewater section of Chicago, witnesses watched as Alexander Rojo pulled out a handgun and, without saying a word, shot his wife three times, stood over her and fired five more bullets, according to police. He then sat down and shot himself in the head.

"They loved each other, they tried, but it was just the death of their son that just...ruined everything," Nancy Rojo's brother, Felix Mendoza, told the Chicago Tribune. "It messed everything up." Calls by ABCNews.com to neighbors and family were not returned, but a friend told the newspaper, "He took it very hard. ... There was a lot of stress between them. There was a lot of blame going back and forth."

The friend said Rojo had bottled up emotions surrounding his son's death, always showing a positive face to others. Despite the divorce, he still loved his wife."Losing a child is horrible, but put suicide on top and it takes it to another level," said Evelyne Morel, whose 22-year-old son hanged himself in 2008."How one copes with the loss of a child is very individual," said the New Jersey 52-year-old. "I needed to cry about it every night. [My husband] had this stoic approach. This poor guy [Rojo] should have used more words instead of being so macho and not dealing with it."

Only about 16 percent of all couples who experience the death of a child go on to divorce, according to a 2006 survey by the nation's largest bereavement organization, Compassionate Friends. "There's been a lot of misinformation for a long time about marriage break-ups," said the group's public awareness coordinator Wayne Loder. Loder's two children, aged 8 and 5, were killed in a Michigan car crash in 1991. "My wife was told she had to be careful because most marriages ended up in divorce after a child dies," said Loder, 59. "She related to me, 'Can you imagine -- both my children died and now I hear I am going to lose my husband?'"The death of a child is "something no one should ever have to go through," he said. "You never recover from something like this completely. I find I am a new me. After a child dies, no one is the same person."

His marriage did survive, largely because the couple was able to talk openly about their loss and never placed any blame. They were also able to bond in their grief."It's a shared experience only between the husband and wife," said Loder. "If they divorce, there is no longer a spouse who has gone through it with them to bring up memories." "We have learned that while the death of a child can strain a marriage, it doesn't usually end in divorce," he said. "Most married couples that experience this kind of devastation pull together and some even become stronger."

That was not the case with Alexander and Nancy Rojo, whose violent deaths came as a surprise to co- workers in the county sheriff's department. "Nobody who worked with him noticed anything out of the ordinary about him," said Patterson. "There were no signs of anything or any distress."

Alexander Rojo's reaction to grief and loss is a "typical one" for men, according to psychologist Weide. "Feelings are considered a weakness and the man has to be a pillar of the family, in addition to being a corrections specialist," she said. "When he is in uniform, he has to play the tough guy."